Wastewater Treatment Methods Research Articles

APPLICATION OF INNOVATIVE TECHNOLOGIES IN THE FIELD OF WASTEWATER TREATMENT: FOREIGN AND KAZAKHSTANI EXPERIENCE

The article discusses modern innovative technologies used in the field of wastewater treatment. Special attention is paid to the principles of operation, advantages and applications of technologies such as membrane bioreactors, anaerobic reactors, aerobic granular precipitation, photocatalytic and electrochemical purification, as well as bio- and nanofiltration. The analysis of the experience of the implementation of these technologies in various countries, including successful cases demonstrating the improvement of the quality of water resources and increasing the efficiency of water treatment systems. The experience of Kazakhstan is considered separately, where the use of advanced wastewater treatment methods is becoming an important element of environmental safety. A comparative analysis of the effectiveness of the use of technologies in Kazakhstan and abroad is carried out, the main factors influencing the success of their implementation in the country are highlighted.

Identifying and testing adaptive management options to increase river catchment system resilience using a Bayesian Network model

AbstractThe cumulative impacts of future climatic and socioeconomic change threaten the ability of freshwater catchments to provide essential ecosystem services. Stakeholders who manage freshwaters require decision-support tools that increase their understanding of catchment system resilience and support the appraisal of adaptive management options to inform decision-making. Our research aims to test the ability of a Bayesian Network model to identify adaptive management scenarios and test their effectiveness across future pathways to 2050. Using the predominantly arable river Eden catchment (320 km2) in eastern Scotland as a case study, we invited stakeholders from multiple sectors to participate in a series of workshops aimed at addressing water quality issues and achieving good ecological status in the catchment both now and in the future. Our participatory methods helped stakeholders overcome multiple layers of complexity and uncertainty associated with future-focused water management. Outputs of a Bayesian Network model simulated both current and future catchment resilience to inform the identification of six management scenarios. The effectiveness of each management scenario was tested using the Bayesian Network model. Two adaptive management scenarios increased catchment resilience and helped achieve good ecological status; a ‘Best Available Technology’ scenario, including aerobic granular sludge treatment, and a management scenario focused on ‘Resource Centre’, including phosphorus recovery from wastewater treatment works and constructed lagoons for crop irrigation. Stakeholders were interested in a 'Nature Based' management scenario including options such as wetland wastewater treatment methods and rural sustainable drainage systems, which improved water quality in the catchment, but had lower certainty in achieving desired outcome. Findings led to a recognition that innovative and collaborative action was required to improve current and future freshwater conditions.

How can a cost-effective method for industrial wastewater treatment be developed in India?

Wastewater treatment and repurposing will be pivotal for growing economies as demand for water increases. A sustainable approach toward economic development in India would be treating industrial wastewater for agricultural applications, reducing overall water consumption, and feeding one sector of the Indian economy with effluent from another. To achieve this, a cost-effective and sustainable treatment process needs to be developed. This paper provides a comprehensive analysis of the available methods and equipment for wastewater treatment through a brief literature review. A four-stage treatment was considered, including pretreatment, primary and secondary chemical treatment, and post treatment. The overall process features screening, oil skimming, coagulation, flocculation, sedimentation, aeration, and gravel filter. The most important specifications suitable for India include using spent poly-aluminum chloride as a coagulant and flocculant (CPCB, 2022) and using vertical shaft aerators (Drewnoski, et. al., 2019) and high-efficiency blowers (Bell, et. al., 2011) in the aeration process.

Land saving and promising seasonal performance in novel spiral wetland

Constructed wetlands have been widely employed as an ecological treatment technology. However, compared to conventional wastewater treatment methods, constructed wetlands require a larger land area, which is incompatible with the limited urban land resources where every inch is valuable. To address this issue, this study proposed and constructed a space-saving spiral constructed wetland. Through optimized structural design, the spiral wetland effectively reduced land occupation and maximizes the utilization of each elevation space to 70 %−80 %. Under the same wetland plane area, spiral wetland only uses 1/3 and 2/3 of the land resources of traditional wetland and the slope wetland, respectively. By utilizing high water head, it resolved dynamic issues faced by traditional wetlands. Additionally, aeration and re-aeration occurred during the transfer of rainwater between each layer of the wetland, enhancing its treatment performance. During summer, the average purification rate of COD is 82 %, and the purification efficiency of ammonia nitrogen is almost 100 % in the spiral wetland where it can accommodate large volumes of stormwater resulting from short-term heavy rainfall events while handling greater pollution loads, which challenges associated with significant amounts of storm runoff and instantaneous water flow during summer periods. In winter seasons, overflow from the spiral wetland combined with multi-stage purification alleviated clogging issues commonly encountered by traditional wetlands and enhanced treatment efficiency which remained above 90 %. The spiral wetlands provided a novel approach to resolving conflicts related to land use in urban areas.

Construction of an in-situ Se-linked ZnSe/ZnO heterojunction for efficient photocatalytic U(VI) reduction

U(VI) in nuclear wastewater threatens human health and the environment due to its high toxicity and mobility. Photocatalysis is seen as a promising, simple, low-cost, and sustainable method for wastewater treatment, but existing photocatalysts face challenges like complex preparation and severe electron-hole recombination. In this work, ellipsoidal Se-linked ZnSe/ZnO was in situ constructed using a simple one-pot hydrothermal method, with non-metallic selenium serving as the carrier. In 30 minutes, the removal rate of U(VI) can reach 90.2 % in 100 mg/L U(VI) solution. The reaction kinetics of the optimal Se/ZnSe/ZnO ratio reached 0.14939 min−1, which is nearly 10 times that of pure ZnO. Photocatalytic analysis revealed that introducing Se as the medium for electron transport in the composite material can effectively reduce electron-hole recombination, thereby enhancing photocatalytic efficiency. The results of this study offer a simple and efficient new method for photocatalytic reduction of U(VI) and provide an effective strategy for establishing a conductive medium in the heterojunction using a one-pot hydrothermal method.

Enhancing Wastewater Treatment with Aerobic Granular Sludge: Impacts of Tetracycline Pressure on Microbial Dynamics and Structural Stability.

This study evaluated the efficiency of aerobic granular sludge (AGS) technology in treating wastewater contaminated with tetracycline (TC), a common antibiotic. AGS was cultivated under a TC pressure gradient ranging from 5 mg/L to 15 mg/L and compared with conventional wastewater conditions. The results demonstrated that AGS achieved high removal efficiencies and exhibited robust sedimentation performance, with significant differences in average particle sizes observed under both conditions (618.6 μm in TC conditions vs. 456.4 μm in conventional conditions). Importantly, exposure to TC was found to alter the composition and production of extracellular polymeric substances (EPSs), thereby enhancing the structural integrity and functional stability of the AGS. Additionally, the selective pressure of TC induced shifts in the microbial community composition; Rhodanobacter played a crucial role in EPS production and biological aggregation, enhancing the structural integrity and metabolic stability of AGS, while Candida tropicalis demonstrated remarkable resilience and efficiency in nutrient removal under stressful environmental conditions. These findings underscore the potential of AGS technology as a promising solution for advancing wastewater treatment methods, thus contributing to environmental protection and sustainability amid growing concerns over antibiotic contamination.

Cutting edge technology for wastewater treatment using smart nanomaterials: recent trends and futuristic advancements.

Water is a vital component of our existence. Many human activities, such as improper waste disposal from households, industries, hospitals, and synthetic processes, are major contributors to the contamination of water streams. It is the responsibility of every individual to safeguard water resources and reduce pollution. Among the various available wastewater treatment (WWT) methods, smart nanomaterials stand out for their effectiveness in pollutant removal through absorption and adsorption. This paper examines the application of valuable smart nanomaterials in treating wastewater. Various nanomaterials, including cellulose nanocrystals (CNC), cellulose nanofibrils (CNF), nanoadsorbents, nanometals, nanofilters, nanocatalysts, carbon nanotubes (CNTs), nanosilver, nanotitanium dioxide, magnetic nanoparticles, nanozero-valent metallic nanoparticles, nanocomposites, nanofibers, and quantum dots, are identified as promising candidates for WWT. These smart nanomaterials efficiently eliminate toxic substances, microplastics, nanoplastics, and polythene particulates from wastewater. Additionally, the paper discusses comparative studies on the purification efficiency of nanoscience technology versus conventional methods.

Теоретичне підґрунтя публічного управління у сфері водопостачання та водовідведення

The sphere of water supply and drainage is a critically important component of the socio-economic mechanism, which is characterized by numerous challenges that were actualized in wartime. Aim of this paper is to analyze the main theoretical approaches of public management in the field of water supply and drainage in order to identify the main principles and tools that affect the efficiency and sustainability of the field. The tools of strategic planning, operational management and emergency response are considered as key components of successful management in this area. Emphasis is placed on the special role of developing fair tariff policies and financial support for infrastructure investments. The importance of the legal framework that regulates the sphere, ensuring compliance with environmental standards and protection of consumer rights is highlighted. The environmental aspect of resource management in the field, which includes modern methods of wastewater treatment and minimizing the negative impact on natural water bodies, is considered. It was emphasized that state intervention is a key factor in ensuring equal access to clean water, which is a basic human right according to the United Nations. The problem of natural monopoly in the field is considered through the prism of high capital investments and low elasticity of demand, which limit market competition. Strategies to stimulate competition and improve service quality are explored, including regulating tariffs and encouraging innovation. The example of Scotland, where water supply management is centralized through the creation of a single national company Scottish Water, reveals the effectiveness of such an approach in improving infrastructure and ensuring high quality services with public participation. The importance of a multidisciplinary approach to management in the field is emphasized, with a special emphasis on the stability of the service in wartime. The research may be useful to researchers, state and local authorities, and international organizations. Further perspectives of research include the study of the peculiarities of the application of the theoretical base in the solution of scientific and practical problems in the field in Ukraine during the war.

Examining the photo catalytic potency of annealed and un-annealed ZnO and nickel doped ZnO for degradation of organic pollutants in waste waters

Water scarcity and pollution has increased the need for innovative and effective waste water treatment methods. The presented study aims to tackle this difficulty by synthesizing zinc oxide (ZnO) and nickel (Ni) doped ZnO to improve their photo catalytic capacity. This study examines wastewater treatment and organic pollutant breakdown using nanotechnology. The annealing increases photo catalytic activity by 65%, thereby enhancing efficiency. XRD shows that annealing decreased the average crystal size of pure ZnO and nickel doped ZnO (Ni:ZnO) i.e., for pure ZnO average crystal size is decreased from 23.90 to 20.90 nm and for Ni:ZnO, 34.39–28.65 nm. SEM shows that un annealed samples have agglomerates, while annealed samples are quasi-spherical. Using diffuse reflectance spectroscopy (DRS), the study examines how annealing affects optical band gap. Annealed Ni:ZnO has a band gap of 3.09 eV, which is smaller as compared to un annealed Ni:ZnO (3.18 e V). Similarly, the decline in energy band gap is observed for pure ZnO too. This study highlights the significant capacity of Ni:ZnO, for un annealed and annealed synthesis, to effectively meet the urgent requirements for waste water treatment. The extensive research conducted in this work enhances our comprehension of photo catalytic materials and underscores its potential for practical implementation in addressing waste water-related environmental issues.

Reviewing the Phenomenon of Antimicrobial Resistance in Hospital and Municipal Wastewaters: The Crisis, the Challenges and Mitigation Methods

Antibiotic resistance is a major crisis that the modern world is confronting. This review highlights the abundance of different types of antibiotic resistance genes (ARGs) in two major reservoirs in the environment, namely hospital and municipal wastewater, which is an unforeseen threat to human lives across the globe. The review helps understand the current state of affairs and the whereabouts on the dissemination of ARGs in both these environments. The various traditional wastewater treatment methods, such as chlorination and UV treatment, and modern methods, such as electrochemical oxidation, are discussed, and the gaps in these technologies are highlighted. The need for the development of newer techniques for wastewater treatment with enhanced efficiency is urgently underscored. Nanomaterial applications for ARG removal were observed to be less explored. This has been discussed, and prospective nanomaterials and nanocomposites for these applications are proposed.

A novel persulfate activation strategy by double Z-scheme Bi2O3/CuBi2O4/BiOBr heterojunction: Non-radical dominated pathway for levofloxacin degradation

Persulfate advanced oxidation technology (PS-AOPs) is known as a novel wastewater treatment method. Considering the poor self-stability of Bi2O3/CuBi2O4, we synthesized Bi2O3/CuBi2O4/BiOBr ternary composite material and established the non-radical pathway-dominated peroxymonosulfate (PMS) activation system. The study indicated that BiOBr promoted electron migration on the material surface. Bi2O3/CuBi2O4/BiOBr/Vis/PMS system exhibited excellent catalytic performance (86.83 % within 100 min), significantly higher than Bi2O3/CuBi2O4 (63.19 %) and BiOBr (60.35 %). Furthermore, it has strong catalytic activity and adaptability to various environmental conditions. By quenching experiments and EPR analysis, O2−∙ and 1O2 were the main active species. Finally, possible degradation pathways and intermediates were predicted through liquid mass spectrometer (LC-MS), and toxicity analysis was conducted on levofloxacin (Lev) and intermediates. The degradation mechanism may be attributed to the construction of double Z-scheme heterojunction, photogenerated electron transfer and ROS generation through the redox cycle of Cu2+/Cu+ and Bi5+/Bi3+.

Application of multi index comprehensive evaluation method in the selection of wastewater treatment processes

The study comprehensively evaluates various wastewater treatment processes by using Grey Relational Analysis (GRA) and Analytic Hierarchy Process (AHP) to identify the optimal method for wastewater treatment. To conduct this evaluation, six key indicators were identified and used for assessment: five-day biochemical oxygen demand (BOD5) removal rate, chemical oxygen demand (COD) removal rate, ammonia nitrogen removal rate, total nitrogen removal rate, total phosphorus removal rate, and suspended solid removal rate. Initially, GRA was employed to calculate the grey relational degree of each treatment process based on the weights of the indicators, and the treatment processes were then ranked and analyzed according to these degrees. Subsequently, AHP was applied to construct a judgment matrix, determine the weights of each indicator, and ensure the matrix's rationality through consistency testing. The study reveals significant differences in the performance of various wastewater treatment processes among the indicators, with the Modified A2/O+AO process showing the highest comprehensive performance in the evaluation. The findings provide a scientific basis for improving efficiency, reducing pollution, and guiding policy and technological development.

Triple strategies for process salt reduction in industrial wastewater treatment: The case of coking wastewater

Human activities introduce nutrient elements into wastewater, yet the saline byproducts from treatment are poorly managed. Selecting a low-salt process, without compromising treatment efficacy, is essential for reaching the zero-discharge goal in water treatment. Based on the engineering treatment process of coking wastewater, the source and reduction strategy of salts were studied. The results showed that 73.21 % of the residual salt originated from raw coal, 10.87 % from raw water, and 15.92 % from chemicals, respectively. Triple strategies for process salt reduction (PSR): load salt reduction, technology salt reduction and cyclic salt reduction can bring 0.411 mS/cm·m3, 0.217 mS/cm·m3 and −0.070 mS/cm·m3 salt reduction, and also bring 1.455 CNY/m3, 0.836 CNY/m3 and 0.360 CNY/m3 net present value, respectively. Meanwhile, PSR is also a low-carbon strategy, which will bring about carbon emission reduction of 1.6948 kg CO2-eq/m3, 0.4898 kg CO2-eq/m3 and 1.4082 kg CO2-eq/m3 respectively. The Resource/Carbon source Management-Oxic − Hydrolytic & Denitrification − Oxic (A-OHO) process, incorporating PSR, cuts costs by 27.83–31.66 % and carbon emissions by 18.68–19.54 % compared to conventional wastewater treatment methods. It can be predicted that the PSR in the standard treatment stage can provide a guarantee for the subsequent water reuse and desalination process to reduce project investment and operating costs, and at the same time benefit the macro environment from the aspects of carbon emission reduction and sludge reduction.

Evaluation of enhanced chemical coagulation method for a case study on colloidal liquid particle in wastewater treatment: Statistical optimization analysis and implementation of machine learning

Coal mines are one of the largest sources of energy supply and generate significant volumes of wastewater. Chemical coagulation is one of the most effective methods for wastewater treatment. In this research, ferric and aluminum-based coagulants, along with polyacrylamide flocculants with positive, negative, and neutral charges, were utilized in chemical coagulation. After applying the Plackett-Burman screening method, it was found that ferric chloride coagulant, neutral flocculant, and slow mixing duration had the greatest impact. The chemical coagulation process was modeled and optimized by examining these factors using the Box–Behnken statistical design as input parameters and sedimentation velocity as the output. Under optimal conditions, the values for ferric chloride coagulant, neutral flocculant, mixing time in slow mode, and sedimentation velocity were determined to be 106.3 mg/L, 3.98 mg/L, 29.6 min, and 1.10 cm/min, respectively. Under optimal conditions, the removal percentages of pollutants, including TSS, turbidity, TDS, COD, and BOD, were obtained at 100%, 100%, 87%, 93%, and 81%, respectively. The experimental data were fitted using the BBD and ANN methods. Both models demonstrated very high agreement, but the ANN method performed better with an AAD% of 0.66, an MSE of 0.0001, and an R2 value of 0.99. All results were calculated with a confidence level above 98%, indicating that both models had very high reliability in modeling and prediction.

The Efficiency of Chemical and Electrochemical Coagulation Methods for Pretreatment of Wastewater from Underground Coal Gasification

This article compares chemical coagulation with electrocoagulation, two popular methods for the primary treatment of wastewater generated in the process of underground coal gasification (UCG). The primary aim was to determine which method is more effective in the removal of cyanide and sulphide ions, metals and metalloids, as well as organic compounds. In both cases, experiments were conducted in batch 1 dm3 reactors and using iron ions. Four types of coagulants were tested during the chemical coagulation study: FeCl2, FeSO4, Fe2(SO4)3, and FeCl3. In the electrocoagulation experiments, pure iron Armco steel was used to manufacture the sacrificial iron anode. Both processes were tested under a wide range of operating conditions (pH, time, Fe dose) to determine their maximum efficiency for treating UCG wastewater. It was found that, through electrocoagulation, a dose as low as 60 mg Fe/dm3 leads to >60% cyanide reduction and >98% sulphide removal efficiency, while for chemical coagulation, even a dose of 307 mg Fe/dm3 did not achieve more than 24% cyanide ion removal. Moreover, industrial chemical coagulants, especially when used in very high doses, can be a substantial source of cross-contamination with trace elements.

Phytoremediation in sustainable wastewater management: an eco-friendly review of current techniques and future prospects

ABSTRACT The sustainable wastewater treatment method known as phytoremediation is reviewed in this paper, with particular attention paid to important technologies including phytoextraction, rhizofiltration, phytostabilization, phytodegradation, and phytovolatilization. The study emphasizes the effectiveness of phytoextraction for heavy metal contamination using hyperaccumulator plants. It also highlights the versatility of phytoremediation by presenting compelling case examples in various situations. This environmentally friendly strategy offers affordable answers to the worldwide water pollution challenge and is in accordance with the growing demand for environmentally aware techniques. Phytoremediation – which emphasizes methods like phytoextraction – becomes a more viable path forward for wastewater pollution mitigation as environmental stewardship advances. By fusing theoretical understanding with real-world implementations, the article advances the conversation on sustainable wastewater treatment while reinforcing phytoremediation's promise for a more environmentally friendly future.

Contaminant of Emerging Concerns in Modder River Catchment of Free State: Implication for Environmental Risk and Water Sources Protection

This study was aimed at monitoring the occurrence and potential sources of emerging contaminants in water sources within the Modder River catchment. Selected water quality indicators were analysed by Hanna multi-parameter meters. Emerging contaminants such as acetaminophen, carbamazepine, ibuprofen, atrazine, simazine, metolachlor, terbuthylazine, 17-alpha-ethinyl-estradiol, estradiol, progesterone, and testosterone were analysed by high performance liquid chromatography mass spectrometry. The sources of emerging contaminants were determined by statistical methods such as Pearson correlation and hierarchical cluster analysis. Results showed that all the sampled water sources have some level of questionable drinking water quality and necessitate some amount of treatment to reduce the contamination before consumption, especially DO, EC, and pH. The 17-alpha-ethinyl-estradiol mean values in rivers (7.79 and 31.55 µg/L), dams (1.83 and 6.90 µg/L), and treated drinking water (0.2 and 0.73 µg/L) were the highest in summer and autumn seasons, respectively. Wastewater effluents, domestic sewage, urban surface runoff, agricultural runoff, and illegal dumping were identified as the possible sources of emerging contaminants pollution. Waste management education, proper application of herbicides, and advance wastewater treatment methods were some of the suggested mitigation strategies. The outcomes may be relevant for environmental protection and water sustainability in the catchment.

Exploring the Adsorption Efficiency of Local Apricot Seed Shell as a Sustainable Sorbent for Nitrate Ion

Locally available apricot seed shell as agro-waste was used for the preparation of adsorbents. The biochar was prepared at 370°C via pyrolysis and 80 mesh particle sizes were modified by 1N HCl. Nitrate adsorption and effect of co-ions from aqueous solution were studied under batch model using apricot seed shell powder (ASSP), apricot seed shell biochar (ASSB), and activated apricot seed shell biochar (AASSB). FTIR and pHPZC measurements were used to characterize the adsorbents. Based on the experimental findings, the optimum conditions follow pH 2, 0.3g dosage, initial concentration of 50 mg.L-1, and contact time of 90 min. The three forms of adsorbent exhibited good adsorption for nitrate. However, the maximum percentage removal of nitrate ions from the aqueous solution followed the order AASSB>ASSB>ASSP. The adsorption kinetic of nitrate ion was best fitted by pseudo 2nd order, and the parameters of adsorption isotherms elucidated favorable and improved sorption. This agro-waste could be used to develop sustainable adsorbents in water and wastewater treatment methods and has great potential to replace commercially available sorbents.

Industrial park wastewater treatment using a combined sono-pulsed electrochemical-coagulation process

Maintaining sustainable water management practices, preserving ecosystems, and safeguarding public health has depend on the treatment of wastewater. It has a significant impact on reducing water pollution and protecting the water supplies. Sono-pulsed electrochemical oxidation (S-PEO) process is a wastewater treatment method that uses ultrasound (US) waves and electrochemistry to enhance the pollutant removal efficiency. This study aim is to investigate the mineralization of industrial park wastewater by using pulsed electrochemical oxidation (PEO) and a combination of sonolysis and pulsed electrochemical oxidation (S-PEO) processes. The research focuses on the percentage elimination of chemical oxygen demand (COD) and color, as well as the assessment of power consumption. The study considers the influence of experimental parameters like initial pH, electrolysis time, and current to find the optimum conditions for maximum percentage removal efficiency with minimization of power consumption. According to the study, the optimum values of responses for the S-PEO process were obtained at pH=7, electrolysis time=40 min, and current =0.5 Amp. The optimum values for the maximum removal percentages of the responses COD and color were 97.04 %, and 99.70 %, respectively. The minimum of power consumption for S-PEO was 0.19 kWh/m3. These results demonstrate that, the superior efficiency of the S-PEO process and its feasibility in the removal of industrial wastewater pollutants. Optimizing parameters like pH, time, and current intensity is crucial for optimal performance, reducing energy consumption and operational costs. The S-PEO technique eliminates pollutants from wastewater efficiently and effectively, making it the suitable process when compared to the others.

Blended natural and synthetic coagulants for the COD and BOD removal from surface water; optimization by response surface methodology: The case of Gibe river

A novel wastewater treatment method is presented in this study. It combines natural coagulants derived from watermelon seeds with the commonly used synthetic coagulant alum. This research demonstrates a remarkable synergy between these two coagulants in removing nutrients from Gibe River wastewater. Combining natural and chemical coagulants often improves water treatment by enhancing particle destabilization, accelerating floc formation, and broadening the range of removable contaminants, resulting in lower chemical dosage requirements. The optimal mixing ratio, found to be 1 part watermelon seed coagulant to 3 parts alum, leads to improved treatment efficiency. At this ratio, the process achieves impressive removal rates: 98.26 % for total dissolved solids (TDS), 96.10 % for biochemical oxygen demand (BOD), and 95.26 % for chemical oxygen demand (COD). These findings not only validate the use of watermelon seeds as a coagulant but also highlight the combined approach's environmental and economic benefits. This integrated method offers a more sustainable and cost-effective solution for wastewater treatment.